<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box {
            width: 400px;
            height: 300px; 
            overflow-x: scroll;
        }
        .ulSS{
            width: 3000px;
            height: 300px;
            border: 1px solid blueviolet;
            overflow-x: scroll;
            /* display: flex; */
            /* flex-wrap: nowrap; */
        }
        .ulSS li {
            width: 200px;
            height: 100px;
            border: 1px solid rgb(15, 111, 190);
            float: left;
            margin-left: 30px;
        }
    </style>
</head>
<body>
    <div class="box">
        <ul class="ulSS">
            <li>1</li>
            <li>2</li>
            <li>3</li>
            <li>4</li>
            <li>5</li>
            <li>6</li>
            <li>7</li>
            <li>8</li>
            <li>9</li>
            <li>10</li>
        </ul>
    </div>
</body>
</html>